It is known to utilize a gas and/or oil high-low pressure control apparatus having a helical bourdon tube sensing a gas and/or oil control pressure and a gap sensor connected to a pressure indicator and rotating between high and low set flags in which the gap sensor controls a pilot actuated valve for controlling a gas supply.
The present invention is directed to various improvements in such an apparatus which increases its life, provides overrange protection, provides a positive snap acting control, an integral gap sensor clean-out, and ease and accuracy of adjustment.